The present invention, in some embodiments thereof, relates to the examination of eggs and, more particularly, but not exclusively, to a method and system for examining eggs, such as, but not limited to, poultry eggs.
In the poultry industry, in particular the chicken industry, discrimination between poultry eggs on the basis of some observable quality is a well-known and long-used practice. “Candling” is a common name for one such technique, a term which has its roots in the original practice of inspecting an egg using the light from a candle. As is known to those familiar with poultry eggs, although egg shells appear opaque under most lighting conditions, they are in reality somewhat translucent, and when placed in front of a direct light, the contents of the egg can be observed.
Candling operations have been done manually for many years. Automatic egg examining devices that utilize the transparency of the egg in order to differentiate between fertilized and unfertilized eggs have been developed over the years. These devices comprise emission means for emitting a light beam in the direction of an egg to be examined, receiving means for receiving the light beam passing through the egg, and means for processing data regarding the light beam received by the receiving means so as to determine the state of the egg. As a function of the level of absorption of the light beam passing through the egg, or the level of transparency of the egg, the data processing means can differentiate between fertilized eggs, i.e., eggs containing an embryo, and unfertilized eggs, including infertile eggs and rotten eggs. Some devices can also differentiate between live fertilized eggs containing a live embryo and dead fertilized eggs containing a dead embryo.
Conventional examining devices comprise a dispatch conveyor for transporting the eggs placed in their horizontal incubation racks or trays, emission means and receiving means being arranged on either side of the dispatch conveyor. In order to obtain satisfactory transparency measurements, the emitters and receivers are conventionally arranged opposite one another in the same vertical plane.
U.S. Pat. No. 6,373,560 discloses apparatus for candling eggs. The apparatus includes an incubation rack with an orifice, a transmission device with an luminous flux source aimed in a direction of the orifice in the incubation rack, a detection device positioned in alignment with the luminous flux source to receive luminous flux through the orifice, and an automatic analyzer connected to the detection device. The detection device and the transmission device are arranged in a substantially vertical plane, one beneath the orifice and the other above the orifice. The apparatus also includes a protection screen for protecting the transmission device or the detection device against smears originating from eggs or the incubation rack.
U.S. Pat. No. 5,898,488 discloses trays of eggs filled with candled eggs wherein infertile eggs are removed from trays of fertile eggs and are replaced with fertile eggs in order to supply a complete array of fertile eggs within the tray.
U.S. Pat. No. 5,745,228 discloses apparatus for distinguishing live from infertile poultry eggs. The apparatus comprises an egg carrier, a light measuring system having a light source positioned on one side of the egg carrier and a light sensor positioned on the other side of the egg carrier opposite the light source, and a switching circuit for cycling the intensity of the light source at a frequency greater than 100 cycles per second.
U.S. Patent Application Publication No. 20100141933 discloses an automatic egg examining device for differentiating between fertilized and unfertilized eggs. The device comprises means for emitting a light beam in the direction of the egg to be examined, means for receiving the light beam passing though the egg, and means for processing data regarding the received light beam in order to determine the fertilized or unfertilized state of the egg. The emission means comprise, for each egg, at least one coherent laser source forming a coherent optical beam in the direction of the egg.
U.S. Patent Application Publication No. 20070024843 discloses a method of candling eggs. An egg is illuminated with light from a light source, and light passing through the egg is received at a light sensor. An output signal that corresponds to the received light is generated and analyzed to determine whether the optical path between the light source and light sensor has been altered.
U.S. Pat. No. 6,535,277 discloses a method of non-invasively identifying a present condition of an egg. The egg is illuminated with light from a light source and light passing through the egg is received at a sensor positioned adjacent the egg. The intensity of the received light at a plurality of the visible and infrared wavelengths is determined, and a spectrum that represents light intensity at selected wavelengths is generated. The generated spectrum is compared with a spectrum associated with a known egg condition.
Great Britain Patent No. GB2166333 discloses a machine for candling eggs. The machine comprises light measuring systems, each including a light source and a sensor. The light measuring systems are arranged such that the eggs are shielded relative to each other.
Additional background art include U.S. Pat. Nos. 4,914.672, 5,745,228, 6,860,225, 7,333,187, 7,611,277 and 7,965,385, U.S. Patent Application Publication Nos. 2005/0206876, 2006/0082759, 2007/0024843, 2007/0024844, 2008/0149033, 2009/0091742, 2009/0091743, 2011/0141455, and International Publication Nos. WO/2003/096028, WO/2002/086495, WO/2003/096028 and WO/2009/044243.